title: Frontal hyperconnectivity related to discounting and reversal learning in cocaine subjects.
abstract: BACKGROUND
  Functional neuroimaging studies suggest that chronic cocaine use is associated with frontal lobe abnormalities. Functional connectivity (FC) alterations of cocaine-dependent individuals (CD), however, are not yet clear. This is the first study to our knowledge that examines resting FC of anterior cingulate cortex (ACC) in CD. Because ACC is known to integrate inputs from different brain regions to regulate behavior, we hypothesized that CD will have connectivity abnormalities in ACC networks. In addition, we hypothesized that abnormalities would be associated with poor performance in delayed discounting and reversal learning tasks.
  
  
  METHODS
  Resting functional magnetic resonance imaging data were collected to look for FC differences between 27 CD (5 women, age: M = 39.73, SD = 6.14 years) and 24 control subjects (5 women, age: M = 39.76, SD = 7.09 years). Participants were assessed with delayed discounting and reversal learning tasks. With seed-based FC measures, we examined FC in CD and control subjects within five ACC connectivity networks with seeds in subgenual, caudal, dorsal, rostral, and perigenual ACC.
  
  
  RESULTS
  The CD showed increased FC within the perigenual ACC network in left middle frontal gyrus, ACC, and middle temporal gyrus when compared with control subjects. The FC abnormalities were significantly positively correlated with task performance in delayed discounting and reversal learning tasks in CD.
  
  
  CONCLUSIONS
  The present study shows that participants with chronic cocaine-dependency have hyperconnectivity within an ACC network known to be involved in social processing and "mentalizing." In addition, FC abnormalities found in CD were associated with difficulties with delay rewards and slower adaptive learning.
authors.affiliation: Department of Psychiatry, University of Minnesota, Minneapolis, 55414, USA. camch001@umn.edu
authors.forename: Jazmin
authors.initials: J
authors.lastname: Camchong
authors.forename: Angus W
authors.initials: AW
authors.lastname: MacDonald
authors.forename: Brent
authors.initials: B
authors.lastname: Nelson
authors.forename: Christopher
authors.initials: C
authors.lastname: Bell
authors.forename: Bryon A
authors.initials: BA
authors.lastname: Mueller
authors.forename: Sheila
authors.initials: S
authors.lastname: Specker
authors.forename: Kelvin O
authors.initials: KO
authors.lastname: Lim
mesh_terms: D000328:Adult; D001931:Brain Mapping; D019970:Cocaine-Related Disorders / Q000503:physiopathology*; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000503:physiopathology*; D009483:Neuropsychological Tests; D012193:Reversal Learning / Q000502:physiology*; D056345:Theory of Mind / Q000502:physiology